When Kevin Youkilis squeezes into a Yankees uniform on Opening Day against the Red Sox at Yankee Stadium, he won’t have erased his days in Boston.

“To say that you negate all the years I played for the Boston Red Sox and all the tradition and you look at all the stuff I have piled up in my house, to say I just throw it out the window, it’s not true,’’ Youkilis said upon checking into the Yankees’ universe yesterday morning at George M. Steinbrenner Field. “I’ll always be a Red Sock. Guys play on different teams but that’s part of history, that’s part of your life and you can’t change that. It was great years in Boston. One bad half year (last season) doesn’t take away all the great years I had there. I saw a Red Sox fan this morning and I bought him coffee and we talked. It’s part of your life, it’s not defining.’’

Nobody knows how long Youkilis will fill in for Alex Rodriguez at third base. It could be until July or it could be the entire season.

Yet, there is one piece of the puzzle Youkilis is certain of: He isn’t Rodriguez.

“You can’t think of shoes to fill because I will never be Alex Rodriguez,’’ a clean-shaven Youkilis said after visiting with Joe Girardi following a red-eye flight from California that got him into town at 6:30 a.m. “He is one of the best hitters of all-time. I am not going to be that same guy. I can be a good major league player who can help the team win.’’

One Yankee whom Youkilis, 34 next month, didn’t get to chat with was Joba Chamberlain. Much was made about Chamberlain, who knocked Youkilis down when he was with the Red Sox, reaching out to Youkilis when he signed and Youkilis not immediately getting back to the reliever. They have communicated via text messages, but it’s believed they haven’t talked.

“I don’t know, it’s something you guys write a lot about, you guys go on and on about,’’ said Youkilis, who is working on a one-year deal worth $12 million. “We are here in spring training and ready to play. That’s drama you guys are creating. Look, all the drama we create this year is walk-off home runs and hits.’’